In 1990, Rossi moved to California, looking for a construction job. Attending a Star Trek convention in Los Angeles, Rossi met writers Trent Christopher Ganino and Eric Stillwell, who offered him a tour of the sets. After Rossi's construction job fell through, he contacted the pair, who got him a job as a tour guide at Paramount Pictures. When a production assistant's position opened up at Star Trek: The Next Generation, Rossi applied and was offered the job. After one season, Rossi was appointed as assistant to Merri Howard, a position he held for three years. He then went on to become assistant to Rick Berman. After the end of The Next Generation, Berman created the position of Supervisor of Star Trek Projects for Rossi, where he worked on attractions, product licensing, and helped oversee Star Trek: Deep Space Nine and Star Trek: Voyager. With the creation of Star Trek: Enterprise, Rossi was promoted to Associate Producer on the series, and was responsible for second unit work in addition to his established duties.